The pervasive influence of corporate cash in the democratic process, and the extraordinary lengths to which politicians, lobbyists and even judges go to solicit money, are laid bare in sealed court documents leaked to the Guardian. The John Doe files amount to 1,500 pages of largely unseen material gathered in evidence by prosecutors investigating alleged irregularities in political fundraising. Last year the Wisconsin supreme court ordered that all the documents should be destroyed, though a set survived that has now been obtained by the news organisation.

The files open a window on a world that is very rarely glimpsed by the public, in which millions of dollars are secretly donated by major corporations and super-wealthy individuals to third-party groups in an attempt to sway elections. They speak to a visceral theme of the 2016 presidential cycle: the distortion of American democracy by big business that has been slammed by both Donald Trump and Bernie Sanders.